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<h1>My ISP, University, company, etc blocks or throttles DC++. What can I do?</h1>
<h2>Blocking and Throttling</h2>
<p>Many <acronym title="Internet Service Provider">ISP</acronym>s, Universities,
or other organizations have policies that limit the usage of peer to peer
applications for their customers, students and employees. Typically, these policies block
or limit the amount of bandwidth that <acronym title="peer to peer">P2P</acronym>
applications can use, and are enforced by packet analizing solutions from <a
 target="_blank" href="http://www.packeteer.com/" class="external">Packeteer</a>,
<a class="external" target="_blank"
 href="http://www.netlogicmicro.com/">NetLogic
Microsystems</a>, or a similar company. This
software/hardware solution has the ability to look into a <acronym
 title="Transmission Control Protocol">TCP</acronym> packet, determine
what class of application created it, then throttle or block it
accordingly.</p>
<p>If you use DC++ from an organization and you're behind such a block,
please learn to live with it. Circumventing the block by proxying is detectable,
is probably against your <acronym title="Acceptable Use Policy">AUP</acronym>, is
technically difficult, and impossible to do without help from someone
outside the firewall.</p>
<p>If your ISP blocks or (heavily) throttles <acronym title="Peer to Peer">P2P</acronym>
connections then you'd better to change to another available provider which does not use
(unacceptable heavily) P2P throttling or blocking techniques.</p>
<p>
You can also try to log on to hubs using the 
<acronym title="Advanced Direct Connect">ADC</acronym> protocol. Since this protocol is
fairly new you have a high chance that the blocking hardware or software can't 
recongnize it. You can find ADC hubs in the 
<a href="window_public_hubs.html#confpublists">configured hublists</a> come with DC++ by default.
The address of an ADC hub always starts with adc:// or adcs:// so puting these to the
Filter box in the hublist window will show you the available ADC hubs right away.
</p>

<h2>Network Address Translation</h2>
<p>Other organizations might have their network behind a <acronym
 title="Network Address Translation">NAT</acronym> in which case an
active connection is impossible. There are also ISP's offering such
kind of access mode (firewalled access). If you're inside a NAT, the IP
reported by your computer will be in one of the <a
 href="non-routable.html">non-routable IP ranges</a>. In this case, try
passive mode.</p>
<p>If you cannot connect to DC hubs or cannot transfer files in passive
mode, the above advice about proxying applies.</p>

<h2>Port Blocking</h2>
<p>A few organizations use simple port blocking, where common ports used by
DC++ and other p2p
applications are blocked. DC++ uses a wide range of ports for outgoing
traffic and incoming traffic by default. If the school blocks port 411
outgoing connections, then that effectively cuts you off from all DC
hubs since that is the default hub port. Hub lists contain the full
address of many hubs and those that run on non-standard ports (<i>i.e.
hub.example.com:1411</i>) may work. Some ISPs (according to the 
<a target="_blank" href="http://www.iana.org/assignments/port-numbers"
class="external">IANA recommendations</a>) may not allow all ports
for incoming P2P transfers. In this case you need to choose any port within the
region of 49152 - 65535 for the port fields in the 
<a href="settings_connection.html">Connection Settings</a>. </p>
<p>If you appear to be completely blocked from the DC network, the
above advice applies.</p>
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